Mars Curiosity Tweetup in Canberra!

On 25 November 2011, NASA will launch the Mars Science Laboratory mission in the form of the rover known as Curiosity, which will be the third such rover to be trundling about the red planet. Curiosity (follow on Twitter as @MarsCuriosity) is larger than the previous two, Spirit, which famously became bogged, ran down its battery and froze during the cold southern Martian winter, and Opportunity, which is still trundling about.

Around the world, a few selected space buffs, educators, writers, artists and other assorted people will be watching the launch behind the scenes. In NASA-speak this is known as a Tweetup, since the main mode of communication is via Twitter.

I am delighted to be one of the people selected for the Canberra event, which will be held at the Deep Space Network Centre at Tidbinbilla. This 24-hour long space geek fest will be coordinated by CSIRO and NASA, joint operators of the site, and in specific Vanessa Hill and Glen Nagle. Vanessa has been sending us tweets with information and asked if we would like to write some tweets about the MSL press kit. But there is so much stuff in there, way too much for little bites of 140 characters, so here is a blog post.

First, a few basics. Curiosity is about 3m long and 2m wide and 2m tall. It has six wheels that can be operated individually, to avoid getting bogged like Spirit. Curiosity weighs 899kg, but in the gravity of Mars that will only appear a third of that.

On its approach to Mars, it will be encased in an aeroshell braking the atmosphere, landing equipment and other gear that makes up a total weight of 3892kg. This ensemble has been mounted (last week) on top of an Atlas V 541 rocket, which stands 58m tall and weighs 535,000kg fully fuelled (remember this post? Yeah, that. More than 90% of the total weight of the vehicle is dedicated to getting off this rock).

There are loads of images of Curiosity in real life and artists’ impressions on the MSL site.

The journey.

You can’t launch a rocket to Mars every day of the year. Mars orbits the Sun roughly once for each two Earth years, so a launch window opens once every two years (more precisely 26 months). This year, that will be from 25 November until 18 December.

The journey is 570 million kilometres, and at the time of landing, the time lag for radio contact will be about 12 minutes.

Curiosity will land on Mars on 5 or 6 August, at about 3pm, local time–heee, I like that. I’m left to wonder how ‘local time’ is defined and what they do with the spare 39 minutes in the Martian day.

The landing site will be the Gale Crater, 4.5 degrees South, 137 degrees East. The Gale Crater is a meteorite impact site believed to be about 3.5 to 3.8 billion years old near the border of the lowlands of Elysium Planitia. It is 154km in diameter, and–and this is what makes it interesting–4.5km deep. More about this later.

At this stage the mission is planned to run for one Martian year (98 weeks).

So what is Curiosity going to do there?
The mission is to study evidence of past or present habitable environments. ‘Habitable environments’ are here defined as ones where water exists as a liquid. Scientists agree that Mars has been wet. Life, if any, would have been microbial. In fact, it has already been determined that liquid water does exist on Mars, in specific environments, such as underground, where remnant heating from past volcanism would keep water liquid, or in places where it gets warm enough and there is enough surface pressure for liquid water to exist.

This is where the site selection comes in. The average surface temperature of Mars is -53C, but in summer, when Mars is closest to the sun (Mars has a much more elliptical orbit than Earth), and in favourable spots, the temperature can creep up to as high as 27C. This is most likely to happen in spots that are sheltered, and at low altitude. There have been signs that liquid water could exist near the selected landing site.

Curiosity has instruments to view the surroundings both at a distance and close up. It will be able to analyse rock, soil and atmosphere samples. It monitors the weather, including radiation, in view of a possible manned mission. Curiosity alone will not be able to determine conclusively whether life exists–or has once existed–on Mars, but will be part of a larger program that gathers evidence one way or another. Just like Earth has many different environments, so does Mars, and because Mars has no oceans, its land surface area is about the same as that of Earth. That is a lot of planet to cover.

What are we going to do in Canberra? Well, the launch will be late–or early depending on your point of view–but apart from that, I haven’t seen the program, but Canberra will be the first Earth tracking station to hear from Curiosity after it has separated from all the rockets and boosters. I’m sure that will feature in the program.

More posts will certainly follow.

Some of you may have seen me tweet with the hashtag #CSIROTweetup; that is what it’s about. There are 49 other people around the country (and one American) who will be coming and this is how we keep in contact.

I leave you with some images from our trip to JPL when I was at the Writers of the Future workshop.
In the control room at JPL